The military said that air defense forces fired a Patriot surface-to-air missile at the aircraft shortly after it was detected approaching the border from Syria, its intentions unclear.

"A Syrian aircraft infiltrated Israeli airspace. The Israel Defense Forces intercepted the aircraft in mid-flight, using the Patriot air defense system," the army said in a statement, adding that it was reviewing the circumstances of the incident.

The plane traversed the border near the Quneitra area and flew for several seconds within Israel before turning back. It was at this point that it was struck by the Patriot missile, Israel's Ynet News cited a military source as saying.

There were conflicting reports in Israeli media regarding the type of aircraft that was downed. Most identified it as a Russian- made MiG-21. The Jerusalem Post quoted a military spokeswoman as saying it was a Sukhoi.

The military declined comment on most details of the incident, saying only that the aircraft breached Israel's airspace but fell on the Syrian side of the border. Unconfirmed reports said the pilots were seen ejecting from the plane.

Residents of Israeli communities in the vicinity reported hearing loud blasts during the interception.

Israeli daily Ha'aretz noted that this was the first time that the Israeli military has downed a manned Syrian aircraft since the 1982 Lebanon War. Israel has scrambled jets on numerous occasions over the years whenever Syrian aircraft flew suspiciously close to the border, but had never engaged.

In a separate incident on Aug. 31, a Patriot missile shot down an unmanned aerial vehicle that infiltrated Israeli airspace from Quneitra. Lt. Col. Peter Lerner, an IDF spokesman, said at the time that the drone likely belonged to the Syrian regime and strayed into Israel by accident. Patriot missiles downed two UAVs that infiltrated Israel from the Gaza Strip during the recent conflict with Hamas.

It was not immediately clear whether the Syrian jet downed Tuesday entered Israeli airspace intentionally or errantly. Local media quoted unidentified military sources as saying that it was likely en-route to attack rebels battling forces loyal to President Bashar Assad near the border, and was not on a mission to attack Israeli targets, according to Ynet.

The incident marked another so-called "spillover" of the more than three-year-old Syrian conflict into Israeli-held territory adjoining Quneitra, a flash point of fierce battles in recent months between Syrian military forces and rebels assisted by al- Qaida-linked militants who are fighting for control of the strategic crossing.

Israel has stated repeatedly that while it does not interfere in the conflict across its northern border, it will not tolerate any breach of its sovereignty by any of the warring parties.